1. Field of the Invention
The present invention relates to an actinic-ray- or radiation-sensitive resin composition employed in a semiconductor production process for an IC or the like, a circuit board production process for a liquid crystal, a thermal head or the like and other photofabrication processes, and also relates to a method of forming a pattern with the use of the composition. More particularly, the present invention relates to an actinic-ray- or radiation-sensitive resin composition that is suitable when an electron beam or far-ultraviolet rays of wavelength 250 nm or shorter, preferably 220 nm or shorter, are used as an exposure light source, and also relates to a method of forming a pattern with the use of the composition.
In the present invention, the terms “actinic rays” and “radiation” mean, for example, a mercury lamp bright line spectrum, far-ultraviolet rays as produced by an excimer laser, extreme ultraviolet rays, X-rays, an electron beam and the like; the term “light” means actinic rays or radiation.
2. Description of the Related Art
In photosensitive compositions, such as a chemical-amplification resist composition, for use in semiconductor photolithographic processing, etc., especially when an ArF excimer laser (wavelength: 193 nm) is used as a light source, it is beneficial to employ a resin having an alicyclic hydrocarbon group from the viewpoint of transparency and resistance to dry etching.
Stronger acids are demanded for the photosensitive compositions containing the resin having an alicyclic hydrocarbon group. Thus, use is made of compounds that generate perfluoroalkylsulfonic acids, such as triphenylsulfonium trifluoromethanesulfonate or the like.
However, the perfluoroalkylsulfonic acids exhibit high hydrophobicity, so that the photosensitive compositions containing the acid generators that generate these acids have poor affinity to aqueous developers. Thus, it has been likely to encounter the problems that a decrease of sensitivity is caused by deteriorated developability and development residues (scum) occur.
Patent reference 1 discloses photosensitive compositions each containing a compound that generates a specified acid having a perfluoroalkyl group connected by means of a nitrogen atom.
Patent reference 2 discloses compounds that generate a sulfonic acid having a basic nitrogen atom so as to inhibit any change of pattern line width over time from exposure to radiation to post-baking.
Further improvement of various performances, especially exposure latitude and line edge roughness performances, is demanded in accordance with the further enhancement of pattern fineness.